368 BOTANY [Chap. XI 



Letter 689 of two kinds, suggested to me as probable. I have, therefore, 

 been extremely glad to receive the seeds of Heteranthera 

 reniformis. As far as I can make out it is an aquatic plant ; 

 and whether I shall succeed in getting it to flower is doubt- 

 ful. Will you be so kind as to send me a postcard telling 

 me in what kind of station it grows. In the course of next 

 autumn or winter, I think that I shall put together my notes 

 (if they seem worth publishing) on the use or meaning of 

 " bloom," 1 or the waxy secretion which makes some leaves 

 glaucous. I think that I told you that my experiments had 

 led me to suspect that the movement of the leaves of Mimosa, 

 Desmodium and Cassia, when shaken and syringed, was to 

 shoot off the drops of water. If you are caught in heavy 

 rain, I should be very much obliged if you would keep this 

 notion in your mind, and look to the position of such leaves. 

 You have such wonderful powers of observation that your 

 opinion would be more valued by me than that of any other 

 man. I have among my notes one letter from you on the 

 subject, but I forget its purport. I hope, also, that you may 

 be led to follow up your very ingenious and novel view on 

 the two-coloured anthers or pollen, and observe which kind 

 is most gathered by bees. 



Letter 690 To F. Muller. 



[Patterdale], June 21st, 1881. 

 I should be much obliged if you could without much 

 trouble send me seeds of any heterostyled herbaceous plants 

 {i.e. a species which would flower soon), as it would be easy 

 work for me to raise some illegitimate seedlings to test their 

 degree of infertility. The plant ought not to have very small 

 flowers. I hope that you received the copies of Nature, 2 

 with extracts from your interesting letters, and 1 was glad 

 to see a notice in Kosmos on Phyllanthus? I am writing this 



1 See Letters 736-40. 



8 Nature, March 3rd, 1881, Vol. XXIII., p. 409, contains a letter from 

 C. Darwin on " Movements of Plants," with extracts from Fritz Miiller's 

 letter. Another letter, " On the Movements of Leaves," was published in 

 Nature, April 28th, 1881, p. 603, with notes on leaf-movements sent to 

 Darwin by Muller. 



3 " Verirrte Blatter," by Fritz Muller {Kosmos, Vol. V, p. 141, 18,81). 

 In this article an account is given of a species of Phyllanthus, a weed 

 in Miiller's garden. See Letter 687. 



